The present invention relates to a mouth held plate for use in tomography. The plate can be divided into two portions, a gum-shaped inner plate and an arc-shaped symmetric outer plate that are integrally connected to each other. A plurality of cavities for holding a molding substance are disposed on the inner plate, the inner plate is connected to the outer plate at the middle point thereof. The outer plate is provided with a horizontally calibrated x-axis and a vertically calibrated y-axis at each side of the symmetric arc-shaped outer plate. The x-axis and y-axes are accompanied with a grid-marked area respectively. A square hole is disposed adjacent the x-axis on the outer plate for mounting a camera which can take tomograms by consecutive exposures under X-rays. The inner plate is held by the mouth of a patient and bitten by the teeth of the patient at the same time so as to keep the dental data of the patient recorded on the molding substance when it becomes solidified. Such a recording plate permits a spot in the mouth under scrutiny to be precisely pin pointed with the help of the coordinates set by the x-axis and y-axes on the outer plate. Thus, the plate can eliminate the positional misalignments produced in the procedure of tomography as a result of careless movement in operation and mistaken measurement caused by the blockage of facial muscles.
An improved mouth held plate intends to eliminate the conventional problems in the operational procedures of dental diagnosis and analysis by tomography, such as positional misalignments and visual blockage by facial muscles in precise setting of the coordinates of a point in the mouth of a patient.
In general, in conventional tomography, a mounting plate put in the mouth of a patient is commonly used to facilitate the pin pointing of a spot in the mouth of a patient under scrutiny. The patient with the mounting plate held in mouth is positioned in front of a tomograph for taking consecutive tomograms exposed under X-rays at a computer set mean interval for diagnosis or examination by tomography.
Such convention procedures and the tools used in tomography seem acceptable. However, there are still some disadvantages as follows.
1. Positional misalignments are easily produced as a result of the visual blockage to the correct coordinates of a point in a patient's mouth; the positional misalignments produced in the patient's consecutive positioning in front of a tomograph every time; a computer set mean value being not suit for all people under scrutiny because of difference in the width of jaws of patients. So, positional misalignments are easily produced in consecutively exposed tomograms, making the tomograms poor to read in practice. PA1 2. The operational procedures are tedious, time wasting and the cost of such tomography is relatively high as a result of the positional misalignments making the computer taken consecutive tomograms hard to locate correct coordinates. In such a case, repeated alignments, photo shootings inevitably cause waste of time, material, resulting in raise of cost. Besides, consecutive tomograms cause controversy in selection of one proper picture for use. PA1 3. The operation can cause harm to a human body. Even tomography is widely adopted in the dental transplantation because it can provide for an elevation image for analysis before a surgery and for follow-up after a surgery so as to help avoid damage to important physical dissection structure. However, improper tomograms become helpless and can even cause harmful aftermath to a patient if mistakes are not eliminated in advance.